Expansible underreamer



March 18, 1930.

R. R.v cRUM 4 1,750,627

ExPANs'IBLE UNDERREAMER Filed Oct. l5. 1928 Z-Sheets-Sheet l 4 ATTORNEYJr March 18, R R. CRUM K I EXPANSIBLE UNDERREAMER 2 Shoots-Sheet2 m. m ,i A ,3 w .4 Q/V a 5 4 a 1 n l 7 N /f/ Y* 7, f 2 w l N wATTORNEYr Patented Mar. 18, 1930 yUNITED STATES PATENT OFFICE ROLAND B.CRUI, OF WHITTIER, CALIFORNIA, ASSIGNOR TO H. C. SMITH MANUFAC- TURINGCOMPANY, 0F WHITTIER, CALIFORNIA, A CORPORATION OF CALIFORNIA EXPANSIBLEUNDERREAMER Application led October 15, 1928. Serial No. 312,474.

This invention relates to an expansible underreamer having alongitudinally movable cutter arranged to be moved laterally to and fromthe body to expand and collapse the underreamer. The present inventioncontemplates the provision of a sloping surface for engagement by acomplementary surface on a cutter member to cause the cutter member tobe moved laterally on longitudinal movement thereof.

The objects of this invention are to provide an underreamer of thecharacter described having any or all of the following featureshydraulic means for actuating the cutters; such hydraulic means operatedby the pressure of circulation Huid employed in hydraulic drilling; andnovel features of construction contributing to simplicity, durabilityand certainty in operation.

These objects together with other objects and correspondingaccomplishments are obtained by means of the embodiment of my inventionillustrated in the accompanying drawing, in which Fig. 1 is an elevationof an underreamer'; Fig. 2 is a central longitudinal section showing theunderreamer parts incollapsed position; Fig. 3 is a central longitudinalsection showing the underreamer parts in expanded position; Fig. 4 is asection as seen on the line 4.-4 of Fig. 3; and Figs. 5 and 6 aresections as seen on the lines correspondingly numbered in Fig. 1.

Referring more particularly to the drawing, 10 indicates a body having apin 11 at its upper end for attachment to a drill string and a bit 12 atthe lower end for drilling. It will be understood that the. bit forms nopart of the present invention, and that the body of the underreamer maybe constructed for detachably securing drilling tools of variouscharacters thereto. The body is illustrated as formed of two partssecured together by a box and pin connection, the

upper part having a circulation passage 13 extending therethrough. Thelower portion of the bit hasan enlarged cylindric chamber 14 serving asa cylinder for a piston. The circulation passage is vextended throughthe body as indicated by 15 opening through water courses to flush thebit 12. A relief port 16 communicates with the cylinder chamber.Extending longitudinally of the body are three lcavities 17 toaccommodate three cutter members. However, the invention is not limitedto any particular number of cutter members. The cavities are duplicatesof one another as are the cutters disposed therein and it will besuiiicient to de scribe one. The inner wall of a cavity is stepped andintermediate the steps is a ramp 18 sloping upwardly and outwardly. Theouter stepped surface serves as a supporting surface for a bearing blockon the cutter members later described. A slot 19 extendinglongitudinally of the body is formed in the step for accommodating across pin. Ranging downwardly from the cylinder chamber is an opening 2Ofor slidingly receiving a vconnecting rod. A pivot pin 21 spans Vthecavity at its lower end. V

Fulcrumed to the body on the pivot pins 21 are lower shaft blocks 22,each having an elongated slot 23 of such width as to provide for alimited lateral play of the block, there. being a bearing face 24 on theblock to rest against the inner wall yof the cavity in expanded positionof the cutter. 'A socket is provided in each block to receive the end ofa cutter shaft 25 having cutter rollers 26 journalled thereon. At lthe'upper end of shaft 25 and secured thereto isa shaft block 27 having anopening extending therethrough in'which may be disposed a cross pin 28.The opening is enlarged at its outer face to accommodate a nut on theend yof the pin, and the reduced portion is enlarged sufficiently toallow a slight play of the piny in the opening. The inner upper face ofblock 27 is bevelled so as to provide a sloping surface 29 complementaryto the ramp 18. A slot is also provided to accommodate a connecting rodjoined to the cross pin.

Disposed within the piston chamber 14 and secured thereto in anysuitable manner such as by welding or a shrunk fit is a head 30. Thehead has a tubular extension 31 and slidingly mounted thereon is apiston 32. A connecting rod 33 for each cutter is secured to the pistonand at the lower end is attached to a cross pin 28. A. number ofVpassages 34 open from the workingend of fluid under pressure andpassage of the cutters below and out of the casing, the piston 32 willbe moved upwardly carrying the cutter members and causing them to rideoutwardly upon their` ramps into position with the rear faces of theblocks 27 resting against the outer steps and serving as a support forthe upper ends of the cutters.

l/Vhat I claim is 1. In an underreamer, the combination of a body,having a longitudinally extending cavity in its periphery with a steppedinner surface at one end and an outwardly sloping ramp intermediate thesteps, a cutter accommodated in said cavity for longitudinal playtherein and having a connection to said body so that it may be movedlaterally thereon into and out of expanded position, a supporting blocksecured to said cutter adjacent to said ramp, said block having asupporting surface to engage and coact with the outer step and a slopingbearing surface for engaging said ramp to cause said cutter to beprojected upon upward movement thereof into expanded position, acylinder chamber communicating with a source of iuid pressure, a pistonin said cylinder, and a connecting rod for actuating said cutter to movethe latter longitudinally upon introduction of l fluid under pressureinto said chamber so as to cause said block to rideI outwardly over saidramp into position with said supporting lsEurface overlapping the outerstepped surace. l

F". In an underreamer, the combination of a body having a longitudinallyextending cavity in its periphery with a stepped inner surface adjacentone end and an outwardly sloping ramp intermediate the steps, a cutteraccommodated in said cavity for longitudinal play therein and having afulcrum connection to said body so that it may be rocked laterallythereon into and out lof expanded position, a block secured to saidcutter at the end opposite to said fulcrum and having a supportingsurface to engage and coact with the outer step and a sloping bearingsurface for engaging said ramp to cause said cutter to be projected uponlongltudinal .1 movement thereof into expanded position, a

cylinder chamber communicating with a source of fluid pressure, a.piston in said chamber, and a connecting rod for actuating said cutterto move the latter longitudinally upon introduction of fluid underpressure into said chamber so as to cause said 'block to ride outwardlyover said ramp into position with said supporting surface overlappingthe outer step surface.

3. In an underreamer, the combination o'f a body having a longitudinallyextending cavity in its periphery with a stepped inner surface at itsupper end and an outwardly sloping ramp intermediate the steps, a cutter accommodated in said cavity for longitudinal play therein and havinga connection to saidbody so that it may be moved laterally thereon intoand out of expanded position, a block secured to said cutter at itsupper end and having a supporting surface to engage and coact with theouter step and a sloping bearing surface for engaging said ramp toIcause said cutter to be projected upon upward movement thereof intoexpanded position, a cylinder chamber communieating with a source offluid pressure, a piston in said chamber, and a connecting rod foractuating said cutter to move the latter upwardly upon introduction offluid under pressure into said chamber so as to cause said block to rideoutwardly over said ramp into position with said supporting surfaceoverlapping the outer step surface.

4. In an underreamer, the combination of a body having a longitudinallyextending cavity in its periphery with a stepped inner surface at` itsupper end and an outwardly sloping ramp intermediate the steps, a cutteraccommodated in said cavity for longitudinal play therein and having afulcrum connection to said body at its lower end so that it may berocked laterally thereon into and out of expanded position, a blocksecured to said cutter at its upper end and having a supporting surfaceto engage and coact with the outer step and a sloping bearing surfacefor engaging said ramp to cause said cutter to be projected upon upwardmovement thereof into expanded position, a cylinder chambercommunicating with a source of fluid pressure, a piston in said chamber,and a connecting rod for actuating said cutter to move the latterupwardly upon introduction of fluid under pressure into said chamber soas to cause said block to' ride outwardly over said ramp into positionwith said supporting surface overlapping the outer step surface.

5. In an underreamer, the combination of a body having a longitudinallyextending cavity in its periphery with a stepped inner surface at itsupper end and an outwardly sloping ramp intermediate the steps, a cutteraccommodated in said cavity for longitudinal play therein and having aconnection to said body so that said cutter may be moved laterally intoand out of expanded position, a block secured to said cutter at itsupper end and having a supporting surface to engage and coactwith theouter step and a sloping bearing surface for engaging said ramp to causesaid cutter to be projected upward upon upward movement thereof intoexpanded position, a cylinder chamber in f sloping ramp intermediate thesteps, a cutter accommodated in said cavity for longitudinal playtherein and having a fulcrum connec-Y tion to said body at its lower endso that said cutter may be rocked laterally into and out of expandedposition, a block secured to said cutter at its upper end and having asupporting surface to engage and coact withthe outer step and a slopingbearing surface for engaging said ramp to cause said cutter to beprojected upon upward movement thereof into expanded position, a.cylinder chamber in said body above said cutter communicating with asource of uid pressure,`a'piston in said c linder, and a connecting roddepending om said piston for actuating said cutter and causing it to bemoved-,upwardly upon introduction of fluid pressurejnto said chamber soas to cause said block to ride outwardly over said ramp into positionwith said supporting surface step surface.

7. In an underreamer, the combination of Y a body having alongitudinally extending cavity in-its periphery with an outwardly.sloping ramp .at its upper end, a cutter accommodated in saidfcavityfor-longitudinal play therein and having a connection to said body sothat it niay be moved laterally thereon into and out of expandedposition, a block secured to said cutter at its'upper end and having asloping bearing surface for engaging said ramp -to cause said cutter tobe pron upward movement thereof into a cylinder chamber in said bodycommunicating with a source of fluid* pressure, a piston 1n saidchamber, and-a connecting rod forsaid piston and said cutterto cause thelatter to be moved `upwardly overlapping the outer expande position,

`upon introduction of fluid pressure into said chamber so as tocausesaid block to ride outwardly over .said ramp with said cutter in gexpanded position.

, duction ofl fluid pressure into sai 8. In an underreamer, thecombination of a body having a longitudinally extending cavity in itsperiphery with an outwardly sloping ramp at its upper end, a cutteraccommodated in said cavity for longitudinal play therein and having aconnection to said ody so that it may be moved laterally thereon intoand out of expanded position, a block secured to said cutter at itsupper end and" having a sloping bearing surface for rengaging said rampto cause said cutter to be projected upon upward movement thereof intoexpandedpositon, a cylinder chamber in said body above said cuttercommunicating with a source of fluid pressure, a piston in saidcylinder, a connecting rod depending from said piston for actuating saidcutter and causing it to be moved upwardly upon introduction of fluidpressure into said chamber so as to cause said block to rideoutwardlyover said ramp into position with said cutter projected.

9. In an underreamer, the combination of a body having a longitudinallyextending cavity in its 'periphery with an outwardly sloping ramp at itsupper end, a cutter accommodated in said cavity for longitudinal playtherein and having a fulcrum connec. tion to said body at its lower endso that it .may be rocked laterally thereon into and 'out of expandedposition, a block secured to said icutter at its upper end and having asloping -surface for engaging said'ramp to cause said cutter to beproiected u on upward movement thereof into expand inder chamber in saidbody communicatlng witha sourcev of fluid pressurefa piston in saidcylinder, and a connecting rod for said piston and cutter to actuate thelatter and cause it to be moved upwardly u on introso as to cause saidblock to ride outwardly over said ramp into position-'with said cutterexpanded. f

10. In an underreamer, the combination of a body having a longitudinallyextending cavity in its periphery with an outwardly sloping ramp at itsupper end, a cutter accommodated in said cavity for longitudinal playtherein and having a fulcrum connection to said body so that' itmay berocked laterally thereon into and out of expanded position, ablocksecured to said cutter at its upper end and havin a sloping bearingsurface for engaging said ramp to cause said cutter to be projected uponupward movement 'thereof into expanded position, a cylinder chamber'insaid body above said cutter communicating with a source of fluidpressure, a

Y piston in said cylinder chamber`, and a connecting rod ndepending fromsaid piston for actuating said cutter and causing it toy be moved uwardly upon introduction of Huid pressure lnto said chamber so as tocause said block to ride outwardly over said ramp into ed position, a cylchamber ill position with said cutter in expanded position.

11. In an underreamer', the combination of a body having alongitudinally extending cavity in its periphery with an outwardlysloping ramp at its upper end, a cutter accommodated in said cavity forlongitudinal play therein and having a connection to said body so thatit may be moved laterally thereon into and out of expanded position, ablock secured to said cutter at its upper end and having a slopingbearing surface for engaging said ramp to cause said cutter to beprojected upon upward movement thereof into expanded position, acirculation passage in said body, a piston chamber in said body, apiston in said chamber, a conduit connecting said circulation passage tothe cylinder space below said piston, and a connecting rod for saidpiston and said cutter to actuate the latter and cause it to be movedupwardly upon introduction of circulation pressure into said chamber soas to cause said block to ride upwardly over said ramp into positionwith said cutter expanded.

12. In an underreamer, the combination of a body having a longitudinallyextending cavity in its periphery with an outwardly'sloping ramp at itsupper end,a cutter accommodated in said cavity for longitudinal playtherein and having a connection to said body so that it may be movedlaterally thereon into and out of expanded position, a block secured tosaid cutter at its upper end and having a sloping bearing surfaceengaging said ramp to cause said cutter to be projected upon upwardmovement thereof into expanded position, a circulation passage in saidbody, a piston chamber in said body located above said cutter, a pistonin said chamber, a conduit connecting vsaid circulation passage to thecylinder chamber space below said piston, and a connecting rod dependingfrom said piston for actuating said cutter and causing it to be movedupwardly upon introduction of circulation pressure into said `chamber soas to cause said block to ride outwardly over said ramp into positionwith said cutter expanded.

13. In .an underreamer, the combination of a body having alongitudinally extending' cavity in its periphery with a stepped innersurface at its upper end and an outwardly sloping ramp intermediate theste s, a cutter accommodated in said cavity or longitudinal play thereinand having a connection to said body so that said cutter maybe movedlaterally into and out of expanded position a block secured to saidcutter at its upper end and having a supporting surface to engage f andcoact with the outer step and a sloping bearing surface engaging saidramp to cause sald cutter to be proJected upon upward movement thereofinto expanded position, a

circulation passage in said body, a piston chamber in said body, a.piston in said chamber, a conduit connecting said circulation passage tothe cylinder space below said piston, and a connecting rod for saidpiston and said cutter to actuate the latter and cause it to be movedupwardly upon introduction of circulation pressure into said chamber soas to cause said block to ride outwardly over said ramp into positionwith said supporting surface overlapping the outer step surface.

MQ In an underreamer, the combination of a body having a longitudinallyextending cavity in its periphery with a stepped inner surface at itsupper end and an outwardly sloping ramp intermediate the steps, a cutteraccommodated in said cavity for longitudinal play therein and having afulcrum connection to said body at its lower end so that said cutter maybe rocked laterally into and'out of expanded position, a block securedto said cutter at its upper end and having a supporting surface toengage and coact with the outer step and a sloping bearing surface forengaging said ramp to cause said cutter to be projected upon upwardmovement thereof into expanded position, a circulation passage in saidbody, a piston chamber in said body above said cutter, a piston in saidchamber, a conduit connecting said circulation passage to the cylinderchamber space below said piston, and a connecting rodvdepending fromsaid piston for actuating said cutter and causing it to be movedupwardly upon introduction of fluid pressure to said chamber so as tocause said block to ride outwardly over

